Legionnaires' Disease Outbreak Associated With a Hot Tub Display at the North Carolina Mountain State Fair, September 2019

OBJECTIVES

On September 23, 2019, the North Carolina Division of Public Health identified a legionellosis increase in western North Carolina; most patients had recently attended the North Carolina Mountain State Fair. We conducted a source investigation.

METHODS

Cases were fair attendees with laboratory-confirmed legionellosis and symptom onset within 2 to 14 days (Legionnaires' disease) or ≤3 days (Pontiac fever). We conducted a case-control study matching cases to non-ill fair attendees as control participants and an environmental investigation, and we performed laboratory testing (Legionella bacteria culture and polymerase chain reaction) of 27 environmental samples from fairgrounds and hot tubs and 14 specimens from case patients. We used multivariable unconditional logistic regression models to calculate adjusted odds ratios for potential Legionella exposure sources and risk factors.

RESULTS

Of 136 people identified with fair-associated legionellosis, 98 (72%) were hospitalized and 4 (3%) died. Case patients were more likely than control participants to report walking by hot tub displays (adjusted odds ratio = 10.0; 95% CI, 4.2-24.1). Complete hot tub water treatment records were not kept, precluding evaluation of water maintenance conducted on display hot tubs. Legionella pneumophila sequence types (STs) were consistent among 10 typed clinical specimens (ST224) but distinct from the only positive environmental sample from the fair (ST7 and ST8).

CONCLUSIONS

Hot tub displays were identified as the most likely outbreak source, making this the largest hot tub-associated Legionnaires' disease outbreak worldwide. Following the investigation, the North Carolina Division of Public Health and the Centers for Disease Control and Prevention released guidance on mitigating risk of Legionella exposure from hot tub displays. Results highlight the importance of properly maintaining equipment that aerosolizes water, including hot tubs intended for display purposes only.

Legionella micdadei Aquaticum Infection: a Case Report and Literature Review

BACKGROUND

The goal of the study was to analyze the clinical characteristics of Legionella cases caused by Legionella micdadei and explore the diagnosis and treatment.

METHODS

The pathogen was identified by routine isolation and culture, biochemical identification, serum agglutination test, mass spectrometry identification, and routine PCR. Combined with the related literature review, the clinical diagnosis and treatment of Legionella micdadei were analyzed.

RESULTS

The patient suffered from pulmonary infection caused by Legionella micdadei. After treatment with moxi-floxacin for 2 weeks, the body temperature dropped and the shadow of the lung was completely absorbed after 2 months. Combined with literature analysis, 8 cases of Legionella micetidis, including 7 males and 1 female, aged from 27 to 57 years old, 6 cases with basic diseases, which were treated with azithromycin, erythromycin or levofloxacin, and all of them achieved good therapeutic effect.

CONCLUSIONS

The detection of Legionella should be strengthened in patients with pneumonia whose symptoms have no obvious improvement after antibiotic treatment. Azithromycin, erythromycin or levofloxacin are effective in the treatment of Legionella spp.

INFECTION

A case report of Legionella and Mycoplasma pneumonia: Co-incidence or co-infection?

RATIONALE

Concurrent or sequential coinfections of Legionella pneumophila and Mycoplasma pneumoniae have been reported in the past though infrequently. Distinguishing a true co-infection from cross reactivity is often challenging as the diagnosis is mostly dependent on serological testing.

PATIENT CONCERNS

A 77-year-old male presented with worsening dyspnea, cough with yellow sputum, diarrhea and fever of 2-days duration. Patient had history of chronic obstructive pulmonary disease (COPD) on home oxygen, bronchiectasis, rheumatoid arthritis (on methotrexate and leflunomide), treated pulmonary tuberculosis and 30-pack-year smoking. Chest X-ray showed bilateral interstitial changes with left lower lobe infiltrate. On day 5, his urine antigen for L pneumophila serogroup 1 was reported positive. The following day his serum M pneumoniae IgM antibody titers were reported elevated at 6647 U/mL. Patient was started on antibiotics and placed on non-invasive positive pressure ventilation.

DIAGNOSIS

The patient was diagnosed with possible Legionella and Mycoplasma co-infection.

OUTCOMES

Sputum Mycoplasma polymerase chain reaction (PCR) and serum cold agglutinins were obtained on day 6 and later reported negative. He was treated with azithromycin for 10 days with clinical improvement.

LESSONS

Serological testing alone is an indirect measure with poor sensitivity and specificity and has its own limitations. Urine antigen detection confirms L pneumophila serogroup 1 infection in a patient with suggestive symptoms. However, diagnosis of M pneumonia should be based on combination of tests including serology and PCR to confirm true co-infection.

Comparison of sputum microbiome of legionellosis-associated patients and other pneumonia patients: indications for polybacterial infections

Bacteria of the genus Legionella cause water-based infections resulting in severe pneumonia. Here we analyze and compare the bacterial microbiome of sputum samples from pneumonia patients in relation to the presence and abundance of the genus Legionella. The prevalence of Legionella species was determined by culture, PCR, and Next Generation Sequencing (NGS). Nine sputum samples out of the 133 analyzed were PCR-positive using Legionella genus-specific primers. Only one sample was positive by culture. Illumina MiSeq 16S rRNA gene sequencing analyses of Legionella-positive and Legionella-negative sputum samples, confirmed that indeed, Legionella was present in the PCR-positive sputum samples. This approach allowed the identification of the sputum microbiome at the genus level, and for Legionella genus at the species and sub-species level. 42% of the sputum samples were dominated by Streptococcus. Legionella was never the dominating genus and was always accompanied by other respiratory pathogens. Interestingly, sputum samples that were Legionella positive were inhabited by aquatic bacteria that have been observed in an association with amoeba, indicating that amoeba might have transferred Legionella from the drinking water together with its microbiome. This is the first study that demonstrates the sputum major bacterial commensals and pathogens profiles with regard to Legionella presence.

[Extracorporeal life support for Legionella pneumonia]

BACKGROUND

Legionella species cause 5% of all community acquired pneumonias. However, Legionella pneumonia results relatively often in admission to the intensive care unit (ICU). A significant complication is the development of acute respiratory distress syndrome (ARDS). The ICU mortality rate for Legionella pneumonia is > 30% with conventional treatments.

CASE DESCRIPTION

A 64-year-old male was admitted to the ICU with respiratory failure due to Legionella pneumonia complicated by ARDS. Despite maximum conventional therapy being given, including lung-protective invasive mechanical ventilation and prone positioning, progressive hypoxaemia persisted. In collaboration with an extracorporeal life support (ECLS) centre, venovenous ECLS was initiated. Pulmonary function recovered and the patient was successfully weaned from VV-ECLS after 17 days. After three months of hospitalisation and rehabilitation, the patient was discharged home and able to perform his activities of daily living without assistance.

CONCLUSION

Legionella pneumonia relatively frequently results in ICU admission, and carries a high mortality with conventional treatments. ECLS may offer a solution if conventional therapies are not sufficiently effective.

Severe non-type-1 Legionella pneumophila infection without pneumonia

We present a patient with myalgia and ongoing fever without respiratory symptoms caused by a Legionella pneumophilia infection. We conclude that in patients with fever of unknown origin legionellosis should be considered, even in the absence of pulmonary symptoms. When considering legionellosis, diagnostic tests should include the urinary antigen test.

Legionella pneumonia in cancer patients

Legionella is an important cause of nosocomial and community-acquired pneumonia in both immunocompetent and immunosuppressed patients worldwide; however, the clinical course and optimal antibiotic therapy of Legionella pneumonia (LP) in patients with cancer is uncertain. We studied retrospectively the risk factors, clinical manifestations, and outcome of 49 cancer patients with a positive Legionella culture or direct fluorescent antibody (DFA) over a 13-year period (1991-2003). The majority of patients (82%) had an underlying hematologic malignancy, and 37% were bone marrow transplant recipients; 80% of the patients had active malignancy. Lymphopenia (47%), use of systemic corticosteroids (41%), and chemotherapy (63%) were the most common underlying conditions. The laboratory diagnosis was established by positive Legionella culture (n = 8, 16%), DFA (n = 29, 59%), or both (n = 12, 25%). In 4 patients (8%), a positive DFA was deemed to represent false-positive results. There was no temporal or geographic clustering of cases. The majority of the cases had multilobar (61%) or bilateral (55%) pulmonary involvement. The mean time to response to therapy was 8 days; 18 patients (37%) developed complications requiring prolonged duration of treatment (mean, 25 d). The case-fatality rate was 31%. Two patients had relapse of LP despite appropriate therapy. Improved outcome, especially in those with severe pneumonia, seemed to correlate with the use of a combination of antibiotics. LP is an uncommon infection in our patient population but is associated with significant morbidity and mortality. Treatment of LP in cancer patients may require a prolonged course with a regimen that includes a newer macrolide or quinolone.

Clinical–Environmental Surveillance of Legionellosis: An Experience in Southern Italy

In Italy, although the number of cases of legionellosis notified to the health authorities has significantly increased in recent years, the incidence is still believed to be underestimated. To verify the true frequency and identify the sources of infection, an active clinical-environmental surveillance program was instituted in three hospital facilities in Southern Italy. Between January 2001 and March 2005, a total of 1000 patients admitted to the three hospitals with a diagnosis of pneumonia were enrolled. The urinary antigen and anti-Legionella antibody titre were assayed in each subject, and direct searches for the microorganism were made in biological specimens. Legionellosis was found to be present in 5.9% of the patients. For each of the cases of legionellosis, microbiological surveys were made of the water supply in the public and/or private facilities involved. Overall, 197 water samples of hospital origin and 218 of community origin were analysed: Legionella spp was isolated in 44.2 and 36.7% of the cases, respectively. Comparison of our data with those of the routine surveillance system for the same area (only 7 cases during the period 1997-2000), showed that the frequency of legionellosis is grossly underestimated in Southern Italy. It is therefore necessary to set up more rigorous controls in both hospital and community facilities, so that timely preventive measures can be taken to avoid any further spread of the disease.

Légionellose à Legionella gormanii de découverte fortuite et leucémie lymphoïde chronique : à propos d'un cas et revue de la littérature

Legionellosis due to other species than Legionella pneumophila is rarely described in human cases. It has been reported in immunocompromised patients with respiratory symptoms of pneumonia. We report a case of legionellosis in an immunocompromised 54-year-old man hospitalized for a blood transfusion. A routine pulmonary X- Ray was made and then a bronchoalveolar lavage was collected in which Legionella gormanii was identified. The diagnostic of legionellosis must be considered in all immunocompromised patients presenting with any pulmonary symptoms.

Focal neurological manifestations in Legionellosis

Legionnaires' disease is an atypical pneumonia with protean multisystem manifestations. Neurological involvement in legionellosis is rare and tends to be among the presenting manifestations. We report a previously healthy young lady who developed focal sensory deficits and cerebellar dysfunction after clinical recovery from Legionella pneumonia. The care is unusual for the delayed appearance of striking focal sensory abnormalities and cerebellar dysfunction.

Legionella micdadei pneumonia diagnosed by culture isolation and DNA-dNA hybridization from bronchial lavage fluid

An 80-year-old man was admitted because of dyspnea on effort. We suspected an acute exacerbation of chronic heart failure and idiopathic interstitial pneumonia caused by right-sided pneumonia. A nodular shadow in right upper lobe spread and consolidated into the airspace, and it failed to improve despite administration of meropenem trihydrate, vancomycin hydrochloride and clindamycin. A definitive diagnosis of Legionella micdadei pneumonia was made on the basis of this organism being isolated in culture from bronchial lavage fluid and subsequent identification of Legionella micdadei using DNA-DNA hybridization. The airspace consolidation gradually improved following treatment with intravenous erythromycin and minocycline hydrochloride.

Pneumonia and Osteomyelitis Due to Legionella longbeachae in a Woman with Systemic Lupus Erythematosus

A patient with risk factors of systemic lupus erythematosus, corticosteroid use, and malignancy received a diagnosis of concomitant pneumonia and osteomyelitis caused by Legionella longbeachae. In this report, the first description of Legionella osteomyelitis, previous cases of extrapulmonary Legionella infection are detailed.

Legionella micdadei infection presenting as severe secretory diarrhea and a solitary pulmonary mass

Sixty percent of infections with non-pneumophila species of Legionella are caused by Legionella micdadei. Although diarrhea is a common symptom of legionellosis, including that due to L. micdadei infection, severe, life-threatening diarrhea is rare. We describe a patient with profound secretory diarrhea (secretion rate, up to 8 L/day) that was secondary to culture-proven L. micdadei pneumonia. In addition, a 3-cm pulmonary nodule was detected, which completely resolved after proper treatment for Legionella infection. Resolving pulmonary nodules have been previously reported in association with treatment of L. micdadei infections.

Fatal Case of Community-Acquired Pneumonia Caused by Legionella longbeachae in a Patient with Systemic Lupus Erythematosus

Reported here is a rare case of atypical pneumonia due to a non- pneumophila Legionella sp. that occurred in a young patient with systemic lupus erythematosus. In spite of aggressive treatment, the patient died 24 h following admission to the intensive care unit. Legionella longbeachae was cultured from respiratory tract specimens and identified to the genus level by PCR and to the species level by an immunofluorescence test. Since most current laboratory tests for Legionella spp., including urinary antigen and serology, cannot detect infections caused by non- pneumophila Legionella spp., culture on legionella-selective media should be strongly considered when diagnosing immunosuppressed patients with pneumonia.

Prospective case-control study of chlamydia, legionella and mycoplasma infections in patients with pityriasis rosea

A double-blind placebo-controlled trial reported the benefit of erythromycin in treating pityriasis rosea (PR), a postulated mechanism being the eradication of bacteria susceptible to erythromycin. The aim of this study was to investigate the association between PR and Chlamydia pneumoniae, C. trachomatis, Legionella longbeachae, L. micdadei, L. pneumophila, and Mycoplasma pneumoniae infections. We recruited 13 patients aged seven to 46 years (mean: 26.8 years) diagnosed to have PR in a primary care setting in 18 months. Lesional histopathology was arranged for atypical cases. Clotted blood was collected at initial presentation and four weeks later. Controls were 13 paired age-and-sex-matched patients requiring blood collection for non-dermatological diseases. Serology tests were performed in parallel but were read "blinded" on the acute and convalescent specimens of patients and the control subjects. The serology profiles were not diagnostic of active infection by any of the bacteria studied for all 13 patients. Two patients had four-fold increase in IgG titres against C. pneumoniae, with IgM being negative. Two patients had IgM detectable against L. pneumophila serotype 6 and M. pneumoniae respectively, with no significant rise of the specific IgG. These patients had no symptom or sign of chest infection. The seroprevalence and IgG titres of the study patients for the bacteria investigated were insignificantly different from those of control subjects. We conclude that the bacteria investigated in this study do not play a significant role in the pathogenesis of PR. We believe that anti-inflammatory and immunomodulatary effects might contribute towards the action of erythromycin, if any, in PR.

Serological evidence of Legionella species infection in acute exacerbation of COPD

A prospective study was conducted to identify and characterize hospitalizations for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) with serological evidence of infection with Legionella spp. (Lsp). Two-hundred and forty hospital admissions for AECOPD of 213 patients were included in the study. Paired sera were obtained for each of the admissions and were tested for 41 different serogroups of Lsp, using microimmunofluorescence-serology. Only a significant change in immunoglobulin-G and/or immunoglobulin-M antibody titres was considered diagnostic. In 40 admissions (16.7%) there was serological evidence of infection with Lsp (LspH). Legionella pneumophila 1 was identified in nine admissions, L. pneumophila 3-15 in 19 and nonpneumophila in 22. In 26 LspH (65%) there was serological evidence of infection with at least one other respiratory pathogen. Compared to the 200 admissions without Lsp (NLspH), the LspH patients were younger (p<0.05) and more hypoxaemic (p<0.04). None of the cases in the LspH group had an abrupt onset of disease, compared to 58 (29.0%) in the NLspH group (p<0.0001). The incidence of myalgia/arthralgia was 55% for LspH compared to 37% for NLspH (p<0.03). To conclude, serological evidence of infection with Legionella spp. is common among patients hospitalized with acute exacerbations of chronic obstructive pulmonary disease. In most hospital admissions with serological evidence of infection with Legionella spp. an additional respiratory pathogen can be identified. Acute exacerbation develops gradually in these patients and is characterized clinically by more systemic manifestations than hospital admissions without serological evidence of infection with Legionella spp. The true interpretation and practical relevance of these findings should be determined in further studies.

Legionella micdadei lung abscess in a patient with HIV-associated nephropathy

A patient with end-stage renal disease due to human immunodeficiency-associated nephropathy developed fever, cough and chest pain over a week's duration. He was diagnosed with lung abscess and started on antibiotic coverage. He underwent bronchoscopy because of progression of his illness and persistent fever and bronchoalveolar lavage culture isolated Legionella micdadei. In spite of appropriate antibiotic therapy, the patient remained febrile for 10 days, necessitating chest tube drainage. After a 6-week course of antibiotics and drainage, the patient made an uneventful recovery. Infections due to L. micdadei may be hard to diagnose because of difficulties in isolating this bacteria.

Potential importance of Legionella species as etiologies in community acquired pneumonia (CAP)

Large percentages of patients with community acquired pneumonia (CAP) do not have a defined etiology. Between 1992-1993, 99 acute and convalescent sera were collected from patients with CAP of unknown etiology. The sera were tested using an indirect immunofluorescence antibody assay (IFA) against the following antigens: Legionella pneumophila, serogroups 3,5,6 and 7 and L. longbeachae, L. anisa, L. bozemanii and Legionella-Like Amoebal Pathogens (LLAP). A four-fold rise in titer to at least one of the antigens tested, was seen in 14% of patients; 8% to L. bozemanii, 4% to L. anisa, 2% to S. lyticum, 2% to LLAP 10 and 1% each to LLAP 1, 6 and 9. Two patients reacted to several antigens. These results indicate that other species of legionella may be important in the etiology of CAP. L. bozemanii was the organism identified in the majority of these infections. Better diagnostic studies i.e. cultures, serologies and urinary antigen testing, which recognize legionella isolates other than L. pneumophila serogroup 1 need to be developed.

[Legionella myopericarditis]

Cardiac involvement in legionella infection is rare but it is the most common extra-pulmonary complication. It usually takes the form of pericarditis, but a case of legionella myoparicarditis with global left ventricular hypokinesia on echocardiography has been described. The authors report a case of myopericarditis with massive pulmonary oedema and respiratory distress which regressed clinically and on echocardiography with reduction in chamber dilatation and complete recovery of left ventricular function. Legionellosis was confirmed on serology. The infection was probably contracted during a previous hospital admission, therefore, probably a nosocomial infection. Following the description of this case, a review of the literature is proposed.

Bilateral pleuritis caused by Legionella micdadei

A 58-year-old woman was hospitalized because of progressive respiratory distress. She had a history of myasthenia gravis and invasive thymoma. After thymectomy, she had been administered oral prednisolone and intrathoracic anti-cancer drugs postoperatively. Her chest radiograph revealed bilateral pleural effusions. Legionella micdadei (L. micdadei) was isolated from the pleural effusions, and she was diagnosed as pleuritis caused by L. micdadei. She died despite intensive therapy with mechanical ventilation, drainage tube in the chest and intravenous erythromycin. Although only two cases of Legionellosis caused by L. micdadei have been reported in Japan, clinicians should be aware of L. micdadei as one of the candidates for infection in immunosuppressed hosts.

Search for agents causing atypical pneumonia in HIV-positive patients by inhibitor-controlled PCR assays

Pneumonia is one of the most frequent complications in acquired immunodeficiency syndrome-patients with Pneumocystis carinii as the leading cause. The true prevalence of atypical agents such as Chlamydia pneumoniae, C. trachomatis, Legionella pneumophila and Mycoplasma pneumoniae in this population of patients is unknown as the currently used method for diagnosing these agents is measurement of antibody levels. However, this method is of limited value in human immunodeficiency virus (HIV)-positive patients who may have a compromised antibody response. To evaluate the prevalence of Chlamydia spp., Legionella spp. and M. pneumoniae in HIV-infected patients with pulmonary disease, this retrospective study has applied inhibitor-controlled polymerase chain reaction analyses on 103 bronchoalveolar lavage (BAL) fluids representing 103 episodes of pneumonia in 83 HIV-positive patients. L. pneumophila was detected in 1% of the BAL fluids and M. pneumoniae was found as a coexisting pathogen in 2% of the samples. Chlamydia spp. could not be detected in any of the BAL fluids. By culture and staining methods 106 other microorganisms were detected with P. carinii and Streptococcus pneumoniae as the most frequently occurring. Pneumonia due to Chlamydia pneumoniae, Legionella pneumophila or Mycoplasma pneumoniae seems to be rare in Danish human immunodeficiency virus-infected patients, but might be considered as a possible cause in cases of treatment failure.

Lung abcess complicating Legionella micdadei pneumonia in an adult liver transplant recipient: case report and review

Legionella micdadei (Pittsburgh pneumonia agent) is the second most common cause of Legionella pneumonia, and occurs predominantly in immunocompromised hosts. L micdadei is the cause of nosocomial pneumonia in renal transplant recipients, but has not been described in other adult solid organ transplant recipients. This report describes the first case of L micdadei pneumonia in an adult liver transplant recipient on immunosuppressive therapy. Importantly, this case highlights the difficulties in establishing the diagnosis, as the Legionella urinary antigen is negative, and special culture conditions are required. Furthermore, this case illustrates several atypical clinical features of L micdadei pneumonia in a transplant recipient, including a community acquired mode of transmission, occurrence several years after organ transplantation, and lung abcess formation. The patient was successfully treated with limited surgical resection and quinolone antimicrobial monotherapy.

[Extracorporeal membrane oxygenation for acute respiratory failure induced by Legionella pneumoniae. (Case report)]

We report a case of severe legionella pneumonia with acute respiratory failure, successfully managed with veno-venous extracorporeal membrane oxygenation (VV-ECMO). The patient presented with 4-day history of fever and cough. He was in critical condition, with exacerbated respiratory failure. Mechanical ventilation, volume replacement and antibiotic therapy were initiated. Despite increasing mechanical ventilatory support (FiO2 100%, TV 10 ml/kg, f 30/min, PEEP 5 cmH20), PaO2 fell below 40Torr and life sustaining measures were undertaken. VV-ECMO (flow 30 ml/kg/min) was commenced, and the patient responded well, with an elevation of PaO2. Erythromycin therapy was effective against the pneumonia. VV-ECMO was maintained for 92 hours, mechanical ventilation was successfully discontinued 11 days after and the patient was discharged 82 days after cessation of ventilator support. Serum antibody examination proved legionella infection. VV-ECMO may have a role in the management of patients with acute respiratory failure caused by bacterial pneumonia.

Infective endocarditis due to unusual or fastidious microorganisms

Infective endocarditis due to fastidious microorganisms is commonly encountered in clinical practice. Some organisms such as fungi account for up to 15% of cases of prosthetic valve infective endocarditis, whereas organisms of the HACEK group (Haemophilus parainfluenzae, H. aphrophilus, and H. paraphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae) cause 3% of community-acquired cases of infective endocarditis. Special techniques are necessary to identify these microorganisms. A history of contact with mammals or birds may suggest infection caused by Coxiella burnetii (Q fever), Brucella species, or Chlamydia psittaci. A nosocomial cluster of postsurgical infective endocarditis may be caused by Legionella species or Mycobacterium species. If risk factors that are commonly associated with fungal infections (cardiac surgical treatment, prolonged hospitalization, indwelling central venous catheters, and long-term antibiotic use) are present, fungal endocarditis is possible. Patients with endocarditis and a history of periodontal disease or dental work in whom routine blood cultures are negative might have infection due to nutritionally variant streptococci or bacteria of the HACEK group. Communication between the microbiologist and the clinician is of crucial importance for identification of these microorganisms early during the course of the infection before complications such as embolization or valvular failure occur. In this article, we review the microbiologic and clinical features of these organisms and provide recommendations for diagnosis and treatment.

Legionella feeleii pneumonia and pericarditis

Legionella feeleii pneumonia has been described in seven cases, three of them being immunocompromised. We describe a case of L. feeleii pneumonia and pericarditis in a healthy man. Epidemiological survey was not conclusive. To the best of our knowledge, there have been no previous descriptions of pericarditis caused by this organism.

Lung abscess caused by Legionella micdadei

We describe a case of lung abscess caused by sporadic infection with Legionella micdadei in a patient with AIDS. L micdadei infection can be very difficult to diagnose because the organism stains only weakly Gram negative, requires special culture media, and is not detectable with some direct fluorescent antibody tests that are directed only at Legionella pneumophila. Since it can stain acid fast, it may be confused with mycobacteria. The abscess was successfully treated using antibiotics and percutaneous catheter drainage.

Positive serology to Legionella longbeachae in patients with adult respiratory distress syndrome

In an observational study we measured the Legionella longbeachae antibody titre rise in patients mechanically ventilated for more than eight days during a two-month period. The patients were divided into two groups on the basis of the presence or absence of the adult respiratory distress syndrome (ARDS). In nine patients with ARDS all showed an antibody rise consistent with recent infection with Legionella longbeachae with a rise in titre (six patients) or a high titre after eight to ten days of ventilation (three patients). Three patients without ARDS did not show a rise in titre. Culture of the environment, ventilator circuits, humidifiers and humidification water did not reveal an environmental source of Legionella longbeachae in the Intensive Care Unit. Legionella longbeachae may be implicated as a pathogenic organism in ARDS, or as a secondary nosocomial infection. Alternatively the antibody titre rise may represent an epiphenomenon and may not be related to Legionella longbeachae infection.

[Pericarditis due to Legionella]

Legionellosis is a systemic infectious disease generally affecting the respiratory system. We present a case with repercussions just at the peri-cardiac level. We review the literature and the diagnostic methods. In addition, we discuss the physiopathological theories and we suggest the convenience of looking for this etiology in the cases of pericarditis.

[Legionellosis associated with pneumopathies in São Paulo. Study of the etiologic confirmation by isolation and serology]

The role of Legionella sp as an important pathogen, although reported in many countries, had not been well documented in Brazil. The main objective of the present study is to detect this organism or it's immunological response in patients with pulmonary infections in the city of São Paulo. For this purpose, specific laboratory methodology was introduced to cultivate the agent and demonstrate specific antibodies by serology. Patients from two University centers in São Paulo were studied: 100 from the Hospital Universitario, University of São Paulo with general pulmonary infections and 100 from Hospital das Clínicas, Faculdade de Medicina, University of São Paulo. The latter were selected to exclude pulmonary infections of other bacterial aetiology, and 30 of these were selected from the Renal Transplant Unit. Clinical specimens for cultures included sputum tracheal secretion, pleural, fluid, bronchial washing or lung tissue biopsy. Isolation of Legionella sp was attempted in BCYE medium with and without antibiotics, presumptive diagnosis by biochemical methods and identification through direct immunofluorescence staining and slide agglutination test. Direct evidence of the organism in tissue was attempted by direct immunofluorescence staining. Specific antibodies for Legionella pneumophila serogroup 1 were tested by the indirect immunofluorescence assay. Serology was also carried out in specimens from human contacts with Legionnaires' Disease. Legionella pneumophila serogroup 1 was isolated from two patients, demonstrating the presence of the pathogen in this country. Serology was able to establish present or past infection with the agent in 16 of the 100 patients from Hospital das Clínicas and in only one from Hospital Universitário. In patients considered as high risk groups from Hospital das Clínicas with renal transplantation, serology for present or past Legionellosis was positive in 33% and in 8.5% for community acquired infections. Serology in specimens from Medical personnel in contact with patients of Legionnaires' disease was positive for past infection in one single subject, confirming information already published that direct transmission from person to person is unusual. The introduction of specific methods for laboratorial evidence of Legionella sp infections at the Hospital das Clínicas-Faculdade de Medicina USP community has permitted diagnosis in able time to allow use of specific anti-microbial therapy, with good results.

Western blot analysis of immune response to Legionella bozemanii antigens

The immune response to individual major antigens of Legionella bozemanii was studied in 67 sera from 26 inpatients with febrile disease using immunoblotting techniques. All the patients had fever of unknown origin and showed strong serological reactions to L bozemanii that cross-reacted with Rickettsia typhi, as determined by a standard indirect microimmunofluorescence assay. Sera analysed by western blotting reacted with 12-14 molecular components of L bozemanii with apparent molecular weights ranging from 14,000 to 94,000 daltons. These reactions compared well with a reference system using antisera of rabbits immunised with the same strain of Legionella. The three major cross-reactive components of R typhi were polypeptide antigens of 94,000, 67,000 and 43,000 daltons. It is concluded that western blotting can help in the differential diagnosis of patients with fever of unknown origin whose sera cross-react to L bozemanii and R typhi.

Isolation of Legionella maceachernii from an immunocompromised patient with severe underlying lung disease

OBJECTIVE

To present the first case in Australia in which Legionella maceachernii has been documented as a cause of infection.

CLINICAL FEATURES

A 71-year-old retired carpenter with underlying autoimmune disease and pulmonary fibrosis was admitted to hospital with increasing shortness of breath and fever, and pneumonia was diagnosed.

INTERVENTION AND OUTCOME

He was treated with ampicillin then gentamicin and flucloxacillin and later imipenem but his condition deteriorated with progression of the pneumonia and abscess formation and he died 25 days after admission. Subsequently, L. maceachernii was isolated from three sputum samples collected before the patient died.

CONCLUSION

There is a need for clinical awareness of the value of sputum culture in the diagnosis of infection due to Legionella spp. other than L. pneumophila.

Pneumonitis associated with coinfection by human herpesvirus 6 and Legionella in an immunocompetent adult

The authors report a case of pneumonitis in a young healthy man caused by coinfection with human herpesvirus 6 (HHV-6) and Legionella pneumophila. The patient's course was complicated by severe respiratory, renal, hepatic, and central nervous system dysfunctions, which were believed to be primarily the results of his Legionella infection. Aggressive antibiotic treatment produced no response, and Legionella remained isolatable from lung tissue throughout several weeks of antimicrobial therapy. Human herpesvirus 6 was isolated from a sample of peripheral blood during the acute stage of the patient's illness, and numerous HHV-6--infected macrophages and lymphocytes were detected by immunohistochemical staining of biopsy-derived lung tissue. Paradoxically treatment of the patient with high-dose corticosteroids resulted in dramatic improvement of his condition, including clearance of the Legionella infection. The demonstration that corticosteroids efficiently inhibit HHV-6 replication in vitro suggests that the virus may have contributed to the patient's pneumonitis by enhancing tissue inflammation, by compromising the function of pulmonary macrophages, and, perhaps, by destroying the patient's CD4+ T lymphocytes. Human herpesvirus 6 may be able to function as a synergistic cofactor in lung infections by Legionella and other pathogens.

Legionella myositis

Neuromuscular involvement in patients with legionnaires' disease is common, with serum CK elevations in up to 78% of patients. A few cases have been associated with neuropathy. The mechanism of injury to the neuromuscular system is unknown, but organisms have not previously been found in nerve or muscle. We report the clinical, electrophysiologic, and pathologic findings in a patient with Legionella myositis and motor neuropathy, the first case to demonstrate direct muscle invasion by the Legionella organism.

[Encephalitis in Legionella bozemanii pneumonia]

A 44-year-old man, a known alcoholic and heavy smoker, was hospitalized with high fever and respiratory failure which a few hours later required intubation and artificial ventilation, although the chest x-ray had been unremarkable. Later serial chest x-ray films showed intrapulmonary infiltrations, while Legionella Bozemanii was demonstrated by direct immunofluorescence. Cranial computed tomography was unremarkable, despite the onset of tetraparesis and a severe midbrain syndrome. Cerebrospinal fluid contained merely mild lymphocytic pleocytosis. However, magnetic resonance imaging revealed symmetrical demyelinization foci in the brainstem as a sign of encephalitis. The neurological deficits regressed almost completely after several weeks of antibiotic treatment and rehabilitation measures over several months.